<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>tab3</title>
    <style>
        * {margin:0; padding: 0;}
        ul {
            list-style-type: none;
        }
        .box {
            width: 400px;
            height: 300px;
            border: 1px solid #ccc;
            margin: 100px auto;
            overflow: hidden;
        }
        .hd {
            height: 45px;
        }
        .hd span {
            display:inline-block;
            width: 90px;
            background-color: pink;
            line-height: 45px;
            text-align: center;
            cursor: pointer;
        }
        .hd span.current {
            background-color: purple;
        }
        .bd div {
            height: 255px;
            background-color: purple;
            display: none;
        }
        .bd div.current {
            display: block;
        }
    </style>
</head>
<body>
<div class="box">
    <div class="hd" id="hd">
        <span class="current">体育</span>
        <span>娱乐</span>
        <span>新闻</span>
        <span>综合</span>
    </div>
    <div class="bd" id="bd">
        <div class="current">我是体育模块</div>
        <div>我是娱乐模块</div>
        <div>我是新闻模块</div>
        <div>我是综合模块</div>
    </div>
</div>
<script>
    //分别获取span和div
    var hd=document.getElementById("hd");
    var bd=document.getElementById("bd");
    var spans=hd.getElementsByTagName("span");
    var divs=bd.getElementsByTagName("div");
    //给每个span绑定注册程序
    for(var i=0;i<spans.length;i++){
        var span=spans[i];
        span.nums=i;//同步保留div当前自己时候用的
        //事件处理程序
        span.onmouseover=function(){
            for(i=0;i<spans.length;i++){
                var span=spans[i];
                var div=divs[i];
                span.className="";
                div.className="";
            }
           this.className="current";
            var nums=this.nums
            divs[nums].className="current";
        }
    }
</script>
</body>
</html>